The present invention relates to a power lawn mower.
Power lawn mowers have a cutter housing and a cutter blade accommodated in the cutter housing and mounted on a vertical shaft driven by a power unit to rotate the cutter blade in a substantially horizontal plane.
When cutting the grass, the cut grass tends to be jammed between the cutter blade and the cutter housing, and the jammed grass presents a resistance to the rotation of the cutter blade, resulting in a power loss. To overcome this deficiency, it is customary to provide a large vertical clearance between the cutter blade and the cutter housing. However, such a vertical clearance is not always effective in freeing the cut grass especially when the long grass is cut.
One solution has been to attach fins to the cutter blade for laterally discharging or throwing out grass cuttings. However, the fins are subject to an air resistance leading to a power loss. The fins are therefore not suitable for use in small lawn mowers having low-output engines for rotating cutter blades.
The present invention has been made in an effort to eliminate the shortcoming of the conventional power lawn mowers.